Merge pull request #18 from mcollina/errSerializer

Added the error serializer

README.md

@@ -135,6 +135,7 @@ Into this:
   * <a href="#trace"><code>logger.<b>trace()</b></code></a>
   * <a href="#reqSerializer"><code>pino.stdSerializers.<b>req</b></code></a>
   * <a href="#resSerializer"><code>pino.stdSerializers.<b>res</b></code></a>
+  * <a href="#errSerializer"><code>pino.stdSerializers.<b>err</b></code></a>
 
 <a name="constructor"></a>
 ### pino([stream], [opts])
@@ -324,6 +325,24 @@ It returns an object in the form:
 }
 ```
 
+<a name="errSerializer"></a>
+### pino.stdSerializers.err
+
+Serializes an `Error` object if passed in as an property.
+
+```js
+{
+  "pid": 40510,
+  "hostname": "MBP-di-Matteo",
+  "level": 50,
+  "msg": "an error",
+  "time": 1459433282301,
+  "v": 1,
+  "type": "Error",
+  "stack": "Error: an error\n    at Object.<anonymous> (/Users/matteo/Repositories/pino/example.js:16:7)\n    at Module._compile (module.js:435:26)\n    at Object.Module._extensions..js (module.js:442:10)\n    at Module.load (module.js:356:32)\n    at Function.Module._load (module.js:313:12)\n    at Function.Module.runMain (module.js:467:10)\n    at startup (node.js:136:18)\n    at node.js:963:3"
+}
+```
+
 <a name="rotate"></a>
 ## How do I rotate log files
 

pino.js

@@ -209,9 +209,18 @@ function asResValue (res) {
   }
 }
 
+function asErrValue (err) {
+  return {
+    type: err.constructor.name,
+    message: err.message,
+    stack: err.stack
+  }
+}
+
 module.exports = pino
 
 module.exports.stdSerializers = {
   req: asReqValue,
-  res: asResValue
+  res: asResValue,
+  err: asErrValue
 }

test.js

@@ -107,6 +107,34 @@ function levelTest (name, level) {
     instance[name](err)
   })
 
+  test('passing error with a serializer at level ' + name, function (t) {
+    t.plan(2)
+    var err = new Error('myerror')
+    var instance = pino({
+      serializers: {
+        err: pino.stdSerializers.err
+      }
+    }, sink(function (chunk, enc, cb) {
+      t.ok(new Date(chunk.time) <= new Date(), 'time is greater than Date.now()')
+      delete chunk.time
+      t.deepEqual(chunk, {
+        pid: pid,
+        hostname: hostname,
+        level: level,
+        err: {
+          type: 'Error',
+          message: err.message,
+          stack: err.stack
+        },
+        v: 1
+      })
+      cb()
+    }))
+
+    instance.level = name
+    instance[name]({ err: err })
+  })
+
   test('child logger for level ' + name, function (t) {
     t.plan(2)
     var instance = pino(sink(function (chunk, enc, cb) {